Oil Pressure Relief Valve

[Chrispy300]

I want to remove the oil filter branch off my VH45. I was just going to drill and tap the back of the oil pump and go from there. The only problem I can think of is the pressure relief in the filter tree. Is it really neccessary? Is it just incase the filter gets gunked up and wont flow?

As far as I can tell it's the only pressure valve for the oil pump.

Will it cause any problems having overly high oil pressure?

Anyone make know of any external aftermarket releif valves?

[craigztoyz]

Yes there are numerous aftermarket ones, I was going to do the same, but I am sure that there is one in there that holds oil in, so that it doesn't all drain back, and have to reprime during startup. I thought of cutting off filter housing, and tapping the branch to use. You can also use the branch 's mounting plate, tapped, or make a new one. The 4 bolt mounting works well to keep it flush and secure.

Problems I saw with tapping back of pump- engine mounting is a bit close, and p/s mounting(depending on what you use)

[npez]

I want to remove the oil filter branch off my VH45. I was just going to drill and tap the back of the oil pump and go from there. The only problem I can think of is the pressure relief in the filter tree. Is it really neccessary? Is it just incase the filter gets gunked up and wont flow?

As far as I can tell it's the only pressure valve for the oil pump.

Will it cause any problems having overly high oil pressure?

Anyone make know of any external aftermarket releif valves?

There was a large thread here on NICO that spoke specifically about this. Some discussion around whether the pressure relief was for clogged filter which would bypass the filter in that case, but in general whether it's a clogged filter or something else (i.e. different viscosity oil, etc.) the pressure relief is there to do just that - relieve pressure.

So to answer your question, pressure works in two ways; pressure to the engine and back-pressure towards the oil-pump. If you take the pressure relief valve out while it *may* not damage anything on your engine, the excessive back-pressure on the oil-pump will most likely damage the seals in the pump.

I haven't seen any external units, but someone may make one in the racing space. I looked through summit and didn't see anything. Good luck with your mod.

Thanks,Nick.

[Chrispy300]

Thanks guys I will search for this mysterious thread...

The PS pump is gone, it was rooted anyway and I will be using a MR2 pump. No air con, no PS pump only the alternator to get in the way of turbo pipes

[npez]

Thanks guys I will search for this mysterious thread...

Found it - here you go: zerothread/242533 starts out as one thing but keep reading....

Thanks,Nick.

[Chrispy300]

Thanks Nick, but found it yesterday...

No definitive answer, but sounds like something that should be kept. I'll have a think and a tinker and see what I can dig up at work to rig up. Might be able to use a pilot valve off a water pressure relief valve

[craigztoyz]

In case it helps, What i am doing is Cutting the Filter housing off AFTER the valve, so that there is space to Tig on a Fitting, or Tap for a line, Then use the Dual Filter Mounting system from Summit, with a RX7's huge oil cooler. Yes it still kicks the lines forward and a bit in the way, but moves the housing out of the way.

I was going to take the housing away completely, but the valve is important enough to me to keep.

[darinz]

I've cut it off before the relief valve then had some pipe TIGed on so that the filter now sits in front of the engine. A plate has been welded to the filter housing part and that has been bolted to where the guard for the PS belt use to be. There is now 2 very short pieces of hose that just make it easy to assemble, between the pump and the filter. We have also tapped the back of the plate on the pump for the turbo oil feed.I've tried taking photo's but there isn't much room so nothing really shows up.

[Chrispy300]

I've cut it off before the relief valve then had some pipe TIGed on so that the filter now sits in front of the engine. A plate has been welded to the filter housing part and that has been bolted to where the guard for the PS belt use to be. There is now 2 very short pieces of hose that just make it easy to assemble, between the pump and the filter. We have also tapped the back of the plate on the pump for the turbo oil feed.I've tried taking photo's but there isn't much room so nothing really shows up.

So did you keep the relief valve? Not entirely clear from your description.

[craigztoyz]

Pretty sure he cut it between engine mounting area and valve, and added between the two. If I understood that right.

[SuperHatch]

The oil pressure relief valve is there just to do what it's name implies, relieve pressure. Think of it as a wastegate, once the oil pressure reaches it's set pressure (the spring in the relief valve) it dumps the excess flow back into the oil pan.

You ever notice when your engine is at idle the oil pressure is low, then when it hits X RPM it's at ~90psi, but never goes over that? That's the relief valve doing it's job.

On DSMs where the balance shafts have been removed and the bearing oil ports plugged, there have been reports of oil pressure jumping to 90psi off idle, holding there til 7krpm, then starting to climb again above there, because there relief valve can't flow enough. The remedy was to port the opening.

Bottom line is, the relief valve is important, it is possible to overoil an engine.

[Chrispy300]

Bottom line is, the relief valve is important, it is possible to overoil an engine.

Thanks Steve, that was the sort of answer I was after

[darinz]

Pretty sure he cut it between engine mounting area and valve, and added between the two. If I understood that right.

Yeah that's right. I still have factory relief valve. I've attached a couple of photo's but they aren't very clear as there is no way to get a camera in the right position!

From below

from the side

In front and to the side

In front.

The filter is sitting in front of the motor at about a 45* angle with the top closer to the outside of the motor. (if that makes sense?)

Hope that makes it a bit clearer.

[craigztoyz]

Appreciate it.

You were not kidding about short hose. Interesting solution. Funcionality berofe looks,

[Chrispy300]

Pulled the oil pump today for a look. Turns out the pump has an internal PRV so I think that I will bin the external valve.



My photo's always suck The oil is clean and there is no sludge in there, just looks that way. Need to take then in the sunlight

[darinz]

Appreciate it.

You were not kidding about short hose. Interesting solution. Funcionality berofe looks,

Yeah a pure race vehicle so it is all about working well and being as easy as possible to work on. As for looks, most people just look at the motor and turbo and after they comprehend that, they don't give a **** that it doesn't have any bling!There's a few guy's I race that have fitted SC to there Lexus V8's but they are still long long way behind!

[SuperHatch]

Did some more reasearch since Chrispy found the pump to have a relief valve inside of it.

Turns out, as overengineered as the VH is, there are two valves which serve two different purposes. There is an oil regulator valve, which is inside the pump. I believe this valve serves the function which I described above. It regulates the engine oil pressure.

The valve in the filter housing is an oil relief valve which, as best as I can tell, bypasses the filter. I would assume this is for situations where the filter becomes clogged and the pressure from the pump needs to get to the engine, it provides an alternate route.

Most engines have a certain amount of bypass built into their filter housing designs, but it is often unregulated. On the VH it is regulated.

So on the original question, whether it is ok to remove this valve or not. I would still say you need it, it just serves a different purpose than I originally thought.